1. Field
The present invention relates to a drilling tool for drilling a hole which is driven by an electric motor, an engine, or the like and, particularly, relates to a drilling tool with a dust collector which allows effective collection of dust produced during drilling.
2. Description of the Related Art
A drilling tool is used to drill a hole in stone materials such as a concrete and a brick. The drilling tool drills a hole in a workpiece by driving a drill bit, and includes a general rotary drill, a hammer drill which causes the drill bit to rotate and strike, a vibratory drill, or the like. Since dust is produced when a drilling operation is performed by using the drilling tool, an operator may perform the operation with a dust mask, protective glasses, or the like. In recent years, a drilling tool provided with a dust collector which sucks the dust has been widely used to remove the dust produced during the operation.
For example, JP-A-2004-276194 discloses that an entire drill bit is covered with a bellows member and a dust collection box in a main body of a vibratory drill, and the main body of the vibratory drill is connected to a suction dust collector as a separate device by means of a connecting pipe of the dust collection box. With this method, the entire drill bit is covered with the bellows member and the dust collection box so that high dust collection effect can be expected. However, large-sized bellows member and dust collection box are required, and the suction dust collector as the separate device is also required so that the method lacks portability.
On the other hand, as a drilling tool having a dust collector which is reduced in size, there is a technique disclosed in JP-A-2006-88285. In the technique, a fluid through passage is formed along a shaft center from a rear end of a drill bit, a fluid discharge port communicated to the outside of the drill is formed at a flute portion at the end of the fluid through passage, and compressed air is delivered to the vicinity of the tip end portion of the drill bit by a compressor provided in the outside via the fluid through passage and the fluid discharge port. A dust collection cup is provided in the vicinity of the tip end portion of the drill bit, and dust is sucked by a suction fan which is rotated by a motor of the drilling tool via a pipe. Even in this device, the compressor as an external device is required so that the device lacks portability. In addition, since the device has a special structure in which the fluid through passage is formed in the shaft center portion of the drill bit, the cost is increased.
In order to solve the problem related to the portability described above, it can be considered that, from the technique disclosed in JP-A-2006-88285, the liquid through passage is removed and the connection to the external compressor is omitted, or the device is used without operating the compressor so that the portability is improved. In this case, dust produced during a drilling operation is moved into a dust collection adaptor due to a spiral structure of the drill bit, guided to a dust collection passage by the suction force of the dust collection fan, separated into air and dust by a filter in a dust collection case, and the dust is stored in the dust collection case. During the drilling operation, the main body of the tool is moved toward a work piece, and a dust collection slide portion constructed of a slide pipe a dust collection unit also move with the movement of the main body of the tool so that it becomes possible for the dust collection adaptor to be constantly in contact with the workpiece.
However, there has been a case where the dust is not sufficiently sucked and the dust is leaked from the vicinity of a contacting area of the dust collection adaptor and the drill bit so that an operator has to spend extra time and effort.
The dust produced during the drilling operation is moved into the dust collection adaptor due to the spiral structure of the drill bit and collected by the suction force of the dust collection fan. However, there has been a case where a part of the dust remains inside the drilled hole after the drilling operation, the remaining dust needs to be removed when an anchor or the like is driven into the drilled hole, and the dust is disadvantageously blown off during the operation for removing the dust. In particular, in the drilling operation with the drill bit faced downwardly as well as the drilling operation with the drill bit held laterally, there has been a case where the dust tends to remain inside the drilled hole or in the surrounding area thereof due to the influence of gravity, and the removal operation of the remaining dust requires extra time and effort.
An object of the present invention is to provide a drilling tool having a dust collector which is increased in dust collection efficiency, improved in workability, and reduced in size.